Comparison of the long-term results between surgical and conservative treatment in patients with intermittent claudication

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

Possible roles of 5-HT in vein graft failure due to intimal hyperplasia 5-HT, nitric oxide and vein graft

For vascular occlusive disease, an autologous vein graft is the most suitable conduit for arterial reconstruction. Intimal hyperplasia, resulting from the migration and proliferation of vascular smooth muscle cells, is a major obstacle to patency after vein grafting. The degree to which the function of nitric oxide (NO) in the vein graft is preserved has been reported to be associated with the magnitude of intimal hyperplasia. Serotonin (5-HT) is released from platelets in the vascular system and plays physiological roles in controlling the vascular tone. The subtype receptors contributing to the 5-HT-induced mechanical responses vary by vessel type (artery and vein) and among species (dogs, rabbits, rats, and so on). Recent studies have demonstrated that 5-HT induces vasoconstriction through the activation of 5-HT2A receptors in smooth muscle cells or vasodilatation through the activation of endothelial 5-HT1B receptors in arteries from various animals. However, the effects of 5-HT have not been clarified in grafted veins. We herein demonstrate the responses to 5-HT in un-operated veins and then autogenous vein grafts. Next, we describe the effects of chronic in vivo administration of Rho-kinase inhibitors and 5-HT2A receptor antagonists, both of which reduce the 5-HT-induced contraction and intimal hyperplasia in vein grafts. Further studies targeting 5-HT are required to evaluate its possible benefits for autologous vein grafts with respect to vasospasm, function, and patency.

Quality of Life and Functional Status After Revascularization or Conservative Treatment in Patients With Intermittent Claudication

Revascularization of patients with intermittent claudication (IC) is recommended only for selected patients who have chronic pain or disabling disease. However, improvement in the quality of life (QoL) could justify more widespread use.

Objectives: To determine the effect of conservative treatment and revascularization on the QoL and physical performance of selected patients with IC.

Patients and Methods: This nonrandomized, parallel group, follow-up study included 83 patients with IC at Fontaine stage II. On the basis of interventional opportunities and the risks and benefits, combined with the preference of the patient, 47 patients were treated conservatively and 41 were revascularized. The patients were examined at inclusion and 3 months later. The evaluations included the QoL measure Short Form 36 (SF-36), the Walking Impairment Questionnaire (WIQ), pain-free and maximal walking distance (treadmill at 3 km/h, no incline), maximal isometric knee-extension strength and endurance, and ankle—brachial blood pressure index (ABI).

Results: At baseline, the SF-36 and WIQ scores and the ABI were significantly lower in the patients selected for revascularization. After revascularization, all dimensions of QoL and functional status increased significantly in the patients who underwent revascularisation compared with the patients treated conservatively. The difference in the change in the physical component summary of SF-36 was 29.4% (P < .001), in the total WIQ 63.6% (P = .0002), and in the pain-free and maximal walking distances 313% (P < .001) and 135% (P < .001), respectively. After adjustment for age, smoking, ABI, body mass index (BMI), and baseline values, the differences remained statistically significant.

Conclusion: Revascularization above the knee increased QoL, functional status, and walking distance significantly in patients with moderate IC.

Sarpogrelate hydrochloride reduced intimal hyperplasia in experimental rabbit vein graft

OBJECTIVES

The selective 5-HT(2A) receptor antagonist sarpogrelate has been clinically used for treatment in atherosclerotic diseases. However, it remains unknown whether administration of sarpogrelate inhibits intimal hyperplasia seen in autologous vein grafts. Therefore, we sought to clarify this question using an experimental rabbit vein graft model.

METHODS

Male rabbits were divided into two groups: a control group and a sarpogrelate-treated group. The jugular vein was interposed in the carotid artery in reversed fashion for 4 weeks and intimal hyperplasia of the grafted vein was measured (n = 8, in each group). Acetylcholine (ACh)-induced endothelium-dependent relaxation was tested by precontraction with prostaglandin F(2alpha) (PGF(2alpha), 5 muM) (n = 5, in each). endothelial nitric oxide synthase (eNOS) protein expression and superoxide production of these veins were also assessed.

RESULTS

The suppression of intimal hyperplasia was significantly greater in the sarpogrelate-treated group than in the control group. ACh induced an endothelium-dependent relaxation in the sarpogrelate-treated group (but not in the control group). In endothelium-intact strips from the sarpogrelate-treated group, the nitric oxide (NO) synthase inhibitor nitroarginine enhanced the PGF(2alpha)-induced contraction and blocked the ACh-induced relaxation. Immunoreactive eNOS protein expression was similar between the two groups but superoxide production (estimated from ethidium fluorescence) in endothelial cells was significantly smaller in the sarpogrelate-treated group.

CONCLUSION

The present results indicate that in vivo blockade of 5-HT(2A) receptors leads to an inhibition of intimal hyperplasia in rabbit vein graft. It is suggested that an increased function of endothelium-derived NO through a reduction in endothelial superoxide production may be a possible underlying mechanism for this. These novel findings support the clinical usefulness of sarpogrelate for preventing intimal hyperplasia in vein graft after bypass grafting.

Controlled release of small interfering RNA targeting midkine attenuates intimal hyperplasia in vein grafts

OBJECTIVE

Intimal hyperplasia is a major obstacle to patency after vein grafting. Despite of a diverse array of trials to prevent it, a satisfactory therapeutic strategy for clinical use has not been established. However, sufficient inhibition of early stages of intimal hyperplasia may prevent this long-term progressive disease. Midkine (MK) is a heparin-binding growth factor that was originally discovered as the product of a retinoic acid-responsive gene. We previously demonstrated that MK-deficient mice exhibit a striking reduction of neointima formation in a restenosis model, which is reversed on systemic MK administration. In this study, we evaluated a strategy of using small interfering RNA (siRNA) targeting MK as a therapy for vein graft failure.

METHODS

We first made a highly effective siRNA to rabbit MK. Jugular vein-to-carotid artery interposition vein grafts, which are applied to a low flow condition, were made in Japanese white rabbits. Small interfering RNA mixed with atelocollagen was administrated to the external wall of grafted veins. Cy3-conjugated stabilized siRNA was used to confirm its stability and successful transfer into the vein graft wall. Neointimal hyperplasia was evaluated 4 weeks after the operation. The proliferation index and leukocyte infiltration were determined.

RESULTS

MK expression was induced and reached the maximum level 7 days after operation. Fluorescence of Cy3-labeled siRNA could be detected in the graft wall even 7 days after operation. Knockdown of the gradually increasing expression was achieved by perivascular application of siRNA using atelocollagen. The intima-media ratio and the intima thickness at 28 days after grafting were both reduced >90% by this treatment compared with controls. This phenomenon was preceded by significant reductions of inflammatory cell recruitment to the vessel walls and subsequent cell proliferation in MK siRNA-treated grafts.

CONCLUSIONS

These results suggest that midkine is a candidate molecular target for preventing vein graft failure. Furthermore, for clinical applications of siRNA, a single intraoperative atelocollagen-based nonviral delivery method could be a reliable approach to achieve maximal function of siRNA in vivo. This strategy may be a useful and practical form of gene therapy against human vein graft failure.